I was on PM for about 2 years (or is it 18 months) before anything happened. It wasn't until I jumped from 2000 mg/day to 3000 mg/day that anything happened, and that took 2 months. I was also taking 1800 mg of FG 4x a day plus Now, at the same time, my thyroid medication was being increased, and a working thyroid is needed to get results. I now have lumps behind my nipples, and my moobs (I'm 50 and have had them since I was 7) are getting firmer. I'm off everything at the moment because of an upcoming eye surgery, but intend to resume after the surgery.
I have no idea if NBE has caused a loss in functionality or it has hastened a drop in my T levels because I lost my sex drive and my erections in 2005 from Effexor, and it hasn't returned despite not taking it since the end of 2006. My T level has been dropping for some time since before pursuing NBE, and my total T is just above 200. My free T is in the female range.
It is an interesting paradox for most males who are not planning to transition to female. PM causes breast growth, but tends to lower T enough that men get scared and want off, but then the desire for breasts goes up once the T levels go back up. It is T that drives the desire, but the answer to the desire, PM, causes a loss of that need/desire. Welcome to the nightmare. I decided to see this through to the end because the breasts mean more to me than erections, orgasms, and fertility. Effexor took all of that away from me long ago, so I may as well grow breasts so I can look better in a dress or nightie. Oh, yeah, I crossdress once in a while, but that desire is also driven by T. I think my issue was originally dopamine-related, and the T is a more recent development.